U.S. Pat. Nos. 4,553,124 Malicki and 4,630,490 Malicki disclose strain gauge transducer assemblies for sensing loading such as of a bolt used to fasten two or more members to each other. The strain gauge transducer assembly disclosed by the No. 4,553,124 Malicki patent includes a counterbored bolt that receives a strain gauge transducer having a web portion that is operable to sense tensioning of the bolt shank. The strain gauge transducer assembly of the No. 4,630,490 Malicki patent discloses a strain gauge transducer assembly including a sensing member such as a bolt that receives a strain gauge transducer having a four-sided intermediate portion on which the strain gauges are mounted so as to sense compression applied to the bolt shank. Each of these strain gauge transducer assemblies functions effectively to individually sense either tension or compression loading but is not capable of sensing both types of loading. Also, the construction of each strain gauge requires that the associated bolt be of at least a predetermined size so as to be capable of receiving the web or four-sided intermediate portion on which the strain gauges are mounted. This size limitation makes it difficult to sense loading of smaller bolts such as self-tapping metal screws for which it would be nevertheless desirable to be capable of sensing loading.
Diaphragm type transducers have primarily been used in industry to measure fluid pressure. See, for example, U.S. Pat. Nos. 2,848,892 Hoffman; 3,161,844 Kabell; 3,493,912 Tull et al. 4,267,725 Roth et al.